When textiles are worn and, in particular, physical activity causing perspiration is performed at the same time, textiles quickly lose their fresh smell after washing. Instead of the fresh smell, the odor of sweat arises, which is perceived as unpleasant by the wearer and by other persons.
Most body odors are perceived as unpleasant. The term “body odor” refers to all smellable human body scents emitted through the skin and, in a broader sense, from other body orifices, such as mouth odor, and to odors caused by excrements (urine, feces, flatus). The odor of sweat is typically the most clearly perceptible. Only the secretions of the apocrine sweat glands, which are located primarily in the axillae, have an odor. When the substances contained in axillary sweat, including endogenous fats and proteins, are decomposed by bacteria, odors are produced, which are perceived as unpleasant and often even repulsive.
Unsaturated or hydroxylated branched fatty acids, such as 3-methyl-2-hexanoic acid or 3-hydroxy-3-methylhexanoic acid, or sulfanyl alcohols, such as 3-methylsulfanylhexan-1-ol, are mainly responsible for body odor, more particularly for sweat odor. The body odor itself is influenced by different bacteria that constitute the skin flora. These bacteria form lipases, which decompose the fatty acids into small molecules, such as butanoic acid (butyric acid). Propanoic acid (propionic acid) is also a frequent component of sweat. It is produced when amino acids are decomposed by propionic acid bacteria.
In everyday life, other odors besides body odor are also perceived by humans as unpleasant. In the household, this applies to food remains that have dried onto dishes over a certain period of time, particularly fish or meat remains, the odor of floor soiling, or the odor of small animals that have died.
All of these odors are referred to as malodors in the present invention.